systemd-hibernate-resume@.service initiates the resume from
hibernation. It is instantiated with the device to resume from as the
template argument.
systemd-hibernate-resume only supports the in-kernel hibernation
implementation, known as swsusp[1]. Internally, it works by writing
the major:minor of specified device node to /sys/power/resume.
Failing to initiate a resume is not an error condition. It may mean
that there was no resume image (e. g. if the system has been simply
powered off and not hibernated). In such case, the boot is ordinarily
continued.

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project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2019-03-06. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2019-03-06.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
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of the original manual page), send a mail to man-pages@man7.org
systemd 234 SYSTEMD-HIBERNATE-RESUME@.SERVICE(8)